Hi all:
Here are some results from Popular Photography's silt image contrast testing
of the 1980s. It compares 35-70 mm zooms from Olympus, Canon, and Zeiss (for
the Contax) in the f/3.4, f/3.6, f/4, and f/3.5~4.5 class. The Zeiss is the
clear winner at the 35 and 50 mm settings, with the Canon f/4.0 bettering it
at 70 mm. Clearly second tier was the Canon f/3.5~4.5, which was a bit better
than the Zuiko f/3.6. The latter Zuiko was about 10% better overall than the
f/3.5~4.5 Zuiko, the third tier lens in this grouping.
Popular Photography considered contrast percentages of 60% and above to be
"high," 35-59% to be "medium," and below 35% to be "low."
Compare the Zeiss to the results I previously gave for the Zuiko Auto 50 mm
f/1.8 at comparable apertures. In short, it betters it! It also betters the
Zuiko Auto 35 mm f/2.8 at comparable apertures. Too bad there isn't
comparable testing for the Zuiko Auto 35-80 mm/f/2.8 which Popular Photography
recently called their sharpest zoom ever in this focal length range. Never-
the-less, this should serve us OLY users of more modest needs.
Gary Reese
Las Vegas, NV
**********
Olympus AF 35-70 mm f/3.5~4.5
(probably equal to Zuiko Auto Zoom lens given the identical optical
construction, although perhaps lower than might be expected from a better
centered sample)
Centering: slightly off
At 35 mm (36.8 mm actual) focal length setting:
Center f/3.5=64 f/5.6=78 f/8=71
1/3rd out f/3.5=59 f/5.6=61 f/8=70
2/3rds out f/3.5=55 f/5.6=59 f/8=58
Far edge f/3.5=51 f/5.6=59 f/8=50
Flare: 0.5%
Distortion: Above average barrel
Measured largest aperture: f/3.28
Transmission: 94%
At 50 mm (53 mm actual) focal length setting:
Center f/4=53 f/5.6=70 f/8=80
1/3rd out f/4=48 f/5.6=59 f/8=67
2/3rds out f/4=38 f/5.6=40 f/8=40
Far edge f/4=30 f/5.6=36 f/8=45
Flare 1.05%
Distortion: None
Measured largest aperture: f/4.0
Transmission: 94%
At 70 mm (68.5 mm actual) focal length setting:
Center f/4.5=45 f/5.6=68 f/8=79
1/3rd out f/4.5=33 f/5.6=58 f/8=69
2/3rds out f/4.5=32 f/5.6=40 f/8=46
Far edge f/4.5=36 f/5.6=40 f/8=45
Flare: 1.05%
Distortion: None
Measured largest aperture: f/4.67
Transmission: 94%
Note: Popular Photography likely labeled their graphs wrong with regards to
the largest aperture. I changed the f/3.5 to f/4 for the 50 mm setting and
the f/3.5 to f/4.5 for the 70 mm setting.
**********
Zuiko Auto Zoom 35-70 mm f/3.6
Centering: Perfect (35 and 50 mm), to near perfect (70 mm)
At 35 mm (actual 36.2 mm) focal length:
Center f/3.5=68 f/5.6=69 f/8=68
1/3rd out f/3.5=60 f/5.6=65 f/8=66
2/3rds out f/3.5=51 f/5.6=61 f/8=60
Far edge f/3.5=45 f/5.6=52 f/8=55
Flare: 0.65%
Distortion: Moderate barrel
Measured largest aperture: f/3.44
Transmission: 94%
At 50 mm (actual 50.1 mm) focal length):
Center f/3.5=76 f/5.6=77 f/8=76
1/3rd out f/3.5=68 f/5.6=69 f/8=70
2/3rds out f/3.5=51 f/5.6=55 f/8=50
Far edge f/3.5=44 f/5.6=50 f/8=41
Flare: 0.9%
Distortion: None
Measured largest aperture: f/3.57
Transmission: 94%
At 70 mm (actual 67.85 mm) focal length:
Center f/3.5=68 f/5.6=80 f/8=80
1/3rd out f/3.5=60 f/5.6=69 f/8=71
2/3rds out f/3.5=50 f/5.6=54 f/8=50
Far edge f/3.5=35 f/5.6=45 f/8=50
Flare: 1.05%
Distortion: Very slight pincushion
Measured largest aperture: f/3.75
Transmission: 94%
************
Canon FD 35-70 mm f/3.5-4.5
Centering: near perfect
At 35 mm (actual 36.15 mm) focal length:
Center f/3.5=70 f/5.6=85 f/8=84
1/3rd out f/3.5=61 f/5.6=80 f/8=79
2/3rds out f/3.5=50 f/5.6=60 f/8=62
Far edge f/3.5=31 f/5.6=45 f/8=52
Flare: 0.5%
Distortion: Pronounced barrel
Measured largest aperture: f/ 3.44
Transmission: 92%
At 50 mm (actual 49.46 mm) focal length:
Center f/4=64 f/5.6=80 f/8=80
1/3rd out f/4=60 f/5.6=80 f/8=80
2/3rds out f/4=50 f/5.6=65 f/8=72
Far edge f/4=42 f/5.6=44 f/8=48
Flare: 0.7%
Distortion: None
Measured largest aperture: f/3.96
Transmission: 94%
At 70 mm (actual 67.85 mm) focal length:
Center f/4.5=74 f/5.6=80 f/8=80
1/3rd out f/4.5=55 f/5.6=75 f/8=80
2/3rds out f/4.5=45 f/5.6=68 f/8=71
Far edge f/4.5=27 f/5.6=35 f/8=38
Flare: 0.75%
Distortion: Very slight pincushion
Measured largest aperture: f/4.68
Transmission: 94%
Note: Popular Photography likely labeled their graphs wrong with regards to
the largest aperture. I changed the f/3.5 to f/4 for the 50 mm setting and
the f/3.5 to f/4.5 for the 70 mm setting.
**********
Canon FD 35-70 mm f/4
Centering: Perfect
At 35 mm (actual 36.78 mm) focal length:
Center f/4=79 f/5.6=78 f/8=77
1/3rd out f/4=73 f/5.6=79 f/8=80
2/3rds out f/4=59 f/5.6=65 f/8=71
Far edge f/4=60 f/5.6=70 f/8=70
Flare: 0.7%
Distortion: Above average barrel
Measured largest aperture: f/3.68
Transmission: 91%
At 50 mm (actual 50.1 mm) focal length:
Center f/4=76 f/5.6=78 f/8=78
1/3rd out f/4=75 f/5.6=78 f/8=79
2/3rds out f/4=67 f/5.6=75 f/8=75
Far edge f/4=57 f/5.6=60 f/8=70
Flare: 1.1%
Distortion: Slight barrel
Measured largest aperture: f/ 4.17
Transmission: 91%
At 70 mm (actual 67.85 mm) focal length:
Center f/4=71 f/5.6=75 f/8=75
1/3rd out f/4=65 f/5.6=75 f/8=77
2/3rds out f/4=65 f/5.6=78 f/8=80
Far edge f/4=53 f/5.6=60 f/8=66
Flare: 1.15%
Distortion: None
Measured largest aperture: f/4.08
Transmission: 92%
**********
Zeiss Vario-Sonnar 35-70 mm f/3.4 (for Contax)
Centering perfect (35 mm) to near perfect (50-70 mm)
At 35 mm (actual 35.5 mm) focal length:
Center f/3.4=71 f/5.6=88 f/8=82
1/3rd out f/3.4=70 f/5.6=81 f/8=80
2/3rds out f/3.4=65 f/5.6=80 f/8=78
Far edge f/3.4=59 f/5.6=75 f/8=78
Flare: 0.65%
Distortion: Moderate barrel
Measured largest aperture: f/3.6
Transmission: 96%
At 50 mm (actual 50.7 mm) focal length:
Center f/3.4=74 f/5.6=82 f/8=81
1/3rd out f/3.4=71 f/5.6=79 f/8=80
2/3rds out f/3.4=65 f/5.6=78 f/8=79
Far edge f/3.4=56 f/5.6=76 f/8=78
Flare: 1.1%
Distortion: None
Measured largest aperture: f/3.9
Transmission: 94%
At 70 mm (actual 67.2 mm) focal length:
Center f/3.4=63 f/5.6=80 f/8=74
1/3rd out f/3.4=60 f/5.6=76 f/8=75
2/3rds out f/3.4=60 f/5.6=76 f/8=70
Far edge f/3.4=55 f/5.6=70 f/8=76
Flare: 1.3%
Distortion: Slight pincushion
Measured largest aperture: f/3.95
Transmission: 94%
Note: This is a poor performer in macro mode (@ 0.41:1 magnification) with
high values only in the center, medium values 1/3rd out and low values 2/3 out
and at the far edge. Also note the measured largest apertures. Makes one
wonder why they called this a f/3.4 lens since it is f.3.6 at best.
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